Gonzalez C F, Pettit E A, Valadez V A, Provin E M
Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, USA.
Mol Plant Microbe Interact. 1997 Sep;10(7):840-51. doi: 10.1094/MPMI.1997.10.7.840.
Phytopathogenic strains of Burkholderia cepacia (synonym Pseudomonas cepacia) produce endopolygalacturonase, whereas strains of clinical and soil origin do not. Growth of a phytopathogenic strain (ATCC25416) at elevated temperatures resulted in nonpectolytic derivatives that were either cured of a resident plasmid or contained a plasmid of reduced mass. The resident 200-kb plasmid (pPEC320) in strain ATCC25416 was tagged with Tn5-Mob. The pPEC320::Tn5-Mob (pPEC321) plasmid was mobilized in B. cepacia strains of soil and clinical origin. Transconjugants containing pPEC321 expressed the endopolygalacturonase and showed differential activity on plant tissue. No evidence for self-transfer of pPEC320 or the tagged derivative was observed. A 285-kb cloned fragment from pPEC320 containing the plasmid-borne pehA gene was sequenced and compared to the pehA gene from Erwinia carotovora subsp. carotovora and Ralstonia solanacearum and the polygalacturonase sequence from Lycopersicon esculentum.
洋葱伯克霍尔德菌（同义词洋葱假单胞菌）的植物致病菌株产生内切多聚半乳糖醛酸酶，而临床来源和土壤来源的菌株则不产生。植物致病菌株（ATCC25416）在高温下生长会产生非果胶分解衍生物，这些衍生物要么失去了一个常驻质粒，要么含有质量减小的质粒。ATCC25416菌株中的常驻200 kb质粒（pPEC320）用Tn5-Mob进行了标记。pPEC320::Tn5-Mob（pPEC321）质粒在土壤来源和临床来源的洋葱伯克霍尔德菌菌株中被转移。含有pPEC321的接合子表达内切多聚半乳糖醛酸酶，并在植物组织上表现出不同的活性。未观察到pPEC320或标记衍生物自我转移的证据。对来自pPEC320的一个包含质粒携带的pehA基因的285 kb克隆片段进行了测序，并与胡萝卜软腐欧文氏菌胡萝卜亚种、青枯雷尔氏菌的pehA基因以及番茄的多聚半乳糖醛酸酶序列进行了比较。
